Air filter



FIG. 1 is an isometric view of my new design for an air filter;

FIG. 2 is a top view thereof;

FIG. 3 is a bottom view thereof;

FIG. 4 is a view along line 4—4 in FIG. 2;

FIG. 5 is a view along line 5—5 in FIG. 3;

FIG. 6 is an enlarged sectional view along line 6—6 in FIG. 5;

FIG. 7 is an enlarged sectional view along line 7—7 in FIG. 5;

FIG. 8 is an enlarged sectional view along line 8—8 in FIG. 5; and,

FIG. 9 is an enlarged exploded view of FIG. 8. 

The ornamental design for an air filter, as shown and described. 